The subject matter disclosed herein relates to turbine engines having variable geometry flow components, and more particularly, but not exclusively, to turbine engines having variable stator blades or nozzles.
To improve performance, turbine engines may include one or more rows of variable stator blades or nozzles (“variable nozzles”) configured to be rotated about their longitudinal axes in order to vary flowpath geometry. Such variable nozzles generally permit enhanced efficiency over a wider operability range by controlling the flow of working fluid through the working fluid flowpath via rotating the angle at which the nozzle airfoils are oriented relative to the flow of working fluid. Rotation of the variable nozzles is generally accomplished by attaching a driver arm to each nozzle and then joining the levers to a synchronizing ring disposed substantially concentric with respect to the turbine casing. As the synchronizing ring is rotated by an actuator, the lever arms are correspondingly rotated, thereby causing each of the nozzles to rotate about its longitudinal axis.
Providing variable geometry capabilities to nozzles of turbine engines remains an area of interest because of the improved output and efficiency over a range of part load and ambient conditions. However, existing systems have various shortcomings, including, for example, durability, leakage, constructability, and installation issues related to the assemblies used to translate the necessary torque from the driver arm to the nozzle airfoils. Accordingly, there remains a need for further advances in this area of technology.